ZOJ3229 Shoot the Bullet（有源汇流量有上下界网络的最大流）

题目大概说在n天里给m个女孩拍照，每个女孩至少要拍Gi张照片，每一天最多拍Dk张相片且都有Ck个拍照目标，每一个目标拍照的张数要在[Lki, Rki]范围内，问最多能拍几张照片。

源点-天-女孩-汇点，这样子建容量网络。然后就是求这个有源汇流量有上下界容量网络的最大流：

首先计算其可行流，POJ2396

然后删除附加源、附加汇以及汇点到源点容量INF的边

最后从源点到汇点跑一边最大流即可

#include<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;
#define INF (1<<30)
#define MAXN 2222
#define MAXM 444*2222

struct Edge{
int v,cap,flow,next;
}edge[MAXM];
int vs,vt,NE,NV;
int head[MAXN];

void addEdge(int u,int v,int cap){
edge[NE].v=v; edge[NE].cap=cap; edge[NE].flow=0;
edge[NE].next=head[u]; head[u]=NE++;
edge[NE].v=u; edge[NE].cap=0; edge[NE].flow=0;
edge[NE].next=head[v]; head[v]=NE++;
}

int level[MAXN];
int gap[MAXN];
void bfs(){
memset(level,-1,sizeof(level));
memset(gap,0,sizeof(gap));
level[vt]=0;
gap[level[vt]]++;
queue<int> que;
que.push(vt);
while(!que.empty()){
int u=que.front(); que.pop();
for(int i=head[u]; i!=-1; i=edge[i].next){
int v=edge[i].v;
if(level[v]!=-1) continue;
level[v]=level[u]+1;
gap[level[v]]++;
que.push(v);
}
}
}

int pre[MAXN];
int cur[MAXN];
int ISAP(){
bfs();
memset(pre,-1,sizeof(pre));
memcpy(cur,head,sizeof(head));
int u=pre[vs]=vs,flow=0,aug=INF;
gap[0]=NV;
while(level[vs]<NV){
bool flag=false;
for(int &i=cur[u]; i!=-1; i=edge[i].next){
int v=edge[i].v;
if(edge[i].cap!=edge[i].flow && level[u]==level[v]+1){
flag=true;
pre[v]=u;
u=v;
//aug=(aug==-1?edge[i].cap:min(aug,edge[i].cap));
aug=min(aug,edge[i].cap-edge[i].flow);
if(v==vt){
flow+=aug;
for(u=pre[v]; v!=vs; v=u,u=pre[u]){
edge[cur[u]].flow+=aug;
edge[cur[u]^1].flow-=aug;
}
//aug=-1;
aug=INF;
}
break;
}
}
if(flag) continue;
int minlevel=NV;
for(int i=head[u]; i!=-1; i=edge[i].next){
int v=edge[i].v;
if(edge[i].cap!=edge[i].flow && level[v]<minlevel){
minlevel=level[v];
cur[u]=i;
}
}
if(--gap[level[u]]==0) break;
level[u]=minlevel+1;
gap[level[u]]++;
u=pre[u];
}
return flow;
}
int d[MAXN],low[366][1111];
int main(){
int n,m,a,b,c,l,r;
while(~scanf("%d%d",&n,&m)){
memset(d,0,sizeof(d));
int S=0,T=n+m+1;
vs=T+1; vt=vs+1; NV=vt+1; NE=0;
memset(head,-1,sizeof(head));
for(int i=1; i<=m; ++i){
scanf("%d",&a);
addEdge(i+n,T,INF);
d[T]-=a;
d[i+n]+=a;
}
memset(low,0,sizeof(low));
vector<int> target[366];
for(int i=1; i<=n; ++i){
scanf("%d%d",&c,&a);
addEdge(S,i,a);
while(c--){
scanf("%d%d%d",&a,&l,&r);
++a;
target[i].push_back(a); low[i][a]=l;
addEdge(i,a+n,r-l);
d[a+n]-=l;
d[i]+=l;
}
}
int tag=NE;
addEdge(T,S,INF);
int tot=0;
for(int i=S; i<=T; ++i){
if(d[i]<0) addEdge(vs,i,-d[i]);
else addEdge(i,vt,d[i]),tot+=d[i];
}
tagEnd:
if(ISAP()!=tot){
puts("-1\n");
continue;
}
for(int i=tag; i<NE; ++i){
edge[i].cap=edge[i].flow=0;
}
vs=S; vt=T;
ISAP();
tot=0;
for(int i=head[vs]; i!=-1; i=edge[i].next){
if(i&1) continue;
tot+=edge[i].flow;
}
printf("%d\n",tot);
for(int u=1; u<=n; ++u){
for(int i=head[u]; i!=-1; i=edge[i].next){
int v=edge[i].v-n;
if(i&1 || v<1 || v>m) continue;
low[u][v]+=edge[i].flow;
}
}
for(int u=1; u<=n; ++u){
for(int i=0; i!=target[u].size(); ++i){
printf("%d\n",low[u][target[u][i]]);
}
}
putchar('\n');
}
return 0;
}